Figure 5.

Orientation of the cup prosthesis in all subgroups. The accuracy of cup prosthesis orientation showed little difference between patient-specific instrument (PSI) groups and conventional operation (CO) groups with Crowe I and Crowe II developmental dysplasia of the hip (DDH). However, the accuracy of cup orientation in the PSI groups was much better than that in the CO groups with Crowe III and Crowe IV DDH. The accuracy of the novel PSI in cup prosthesis orientation had a significant advantage over CO in patients with Crowe III and IV DDH, but not in those with Crowe I and II DDH.